This invention relates to the field of solid state electronics and particularly to the field of charge coupled devices (CCDs).
Charge coupled devices have many promising applications such as transversal filtering and matched filtering for communication, signal multiplexing and de-multiplexing, and optical processing. These applications require high speed and good dynamic range.
Prior art CCDs utilize either surface channel designs, for example U.S. Pat. No. 3,654,499; or buried channel designs, for example U.S. Pat. Nos. 4,285,000 and 3,739,240. The surface channel CCDs have a larger total charge store, but their transfer speed is limited because the charge is held closer to the surface. The buried channel CCDs have a higher ultimate transfer speed due to fringing fields, but their total charge store is smaller. Consequently, there is a need for CCDs which have both improved speed and a large charge store.